If TV crime dramas are anything to go by, cold cases are highly unpopular with detectives.

They inevitably lead to tensions with the original investigation team while most of the witnesses have long disappeared.

But in the real world there is an even bigger problem – key evidence can perish over time making it difficult to reap the benefits of technology breakthroughs long after the unsolved crime was committed.

Big changes afoot

That could be about to change however, as the forensic science world stands on the brink of a revolution.

Scientists are working to produce perfect replicas of key crime scene evidence using the latest 3D printing techniques – and they are cautiously optimistic that they will succeed.

If they do, detectives would be able to perfectly preserve key evidence by digitally storing the measurements and printing out a copy whenever one is needed.

CSI: Cold Case?

Not only could this pave the way for a new crime drama franchise – CSI: Cold Case maybe – as forensic testing became more viable in old unsolved cases; it could also help with the cases of today.

3D printouts of artifacts could help detectives solve future ‘cold’ cases in which the physical original has deteriorated – so it can be re-examined if new crime-solving technologies are invented or new evidence comes to light.

They could also help in the original investigation of a crime enabling detectives to conduct tests on exact replicas of evidence that they typically have to leave untouched – and by allowing them to print replicas of key evidence to pass around the courtroom.

“Bones can change over relatively short timescales with moisture and with age, and slight changes can make quite a significant difference,”

Ruth Morgan

“Bones can change over relatively short timescales with moisture and with age, and slight changes can make quite a significant difference,” said Ruth Morgan, director of the centre for forensic sciences at University College London, told i.

“If you look at a feature on a skull caused by a blow to the head soon after it happens it will have important characteristics that are valuable for a forensic expert to examine. But in 25 years time the measurements could be quite different as alterations occur,” said Dr Morgan, who is developing the project with Dr Carolyn Rando and PhD student Rachael Carew.

“If you’re able to preserve exhibits in a digital format, we could produce them again and then apply new technologies we’ve got in the years to come,” she said.

The team is testing different ways of producing 3D artifacts using different resins and plastics to determine which is most effective. They are only a few months into a five year project but Dr Morgan says the early indications are that it could be done relatively cheaply and easily.

“If you look at a feature on a skull caused by a blow to the head soon after it happens it will have important characteristics that are valuable for a forensic expert to examine. But in 25 years time the measurements could be quite different as alterations occur,”

Ruth Morgan

If that were to be the case, we may see 3D evidence becoming quite widespread in courts – which it isn’t now because the risk of damage to key evidence is typically too high and in some cases may be unethical.

“At the moment you wouldn’t bring actual remains into court. But a 3D model could allow a jury to see that evidence and better visualise what is being discussed by the witness. It will enable them to see the degree of any pertinent damage more easily than from the 2D photos or virtual models that are available at the moment,” she said.

Sensitive issues

This particular development would need to be handled with care, however.

“The ethical considerations need to be fully considered as there is potential for this type of evidence to be emotive within in the courtroom. The implications of that need to be looked into to make sure that evidence is presented accurately but sensitively to assist the court,” Dr Morgan added.

3D printers are a new generation of machines that can make pretty much anything from ceramic cups to plastic toys, weapons and bones.

The printing process turns a whole object into thousands of tiny little slices through thousands of precise measurements, then makes it from the bottom-up, slice by slice. Those tiny layers stick together to form a solid object.

This would allow detectives, for example, to print off multiple exact replicas of a victim’s injured bone and conduct a series of tests to determine the precise cause of the wound – the murder weapon that inflicted it, the force involved, and the angle from which it was delivered.

Although these kind of lab tests can already be carried out, this would allow an extra degree of precision that could prove crucial in some cases, Dr Morgan says.

Beware the badly-timed handshake

This is one in a number of forensic science projects UCL is working on.

Another of these studies suggested that a badly timed handshake could see you wrongly convicted for murder.

That’s because forensic tests are now so sensitive that DNA can take long, circuitous journeys and still be detected on items linked to crime, according to research.

Rapid improvements in forensic technology greatly increase the potential to help solve crimes using DNA evidence – but they also risk casting suspicion on innocent people if that evidence is not properly interpreted, she found.

As a result, there are likely to have been wrongful convictions on the basis of DNA being indirectly transferred on to a murder weapon, although this would be hard to prove.

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